Blood

T. Lymphocytes
Function: •
• Cell mediated immunity:-
• When exposed to cellular antigen, the T-lymphocytes are activated and
come in contact with the antigen.
• They secrete cytotoxic substance to destroy it.
• Graft rejection cells in organ transplantation:
• .(by cell mediated immunity)
• T-memory cells:
• Some of the activated T-cells remain in the body as memory cells, that
can attack the same antigen after a long period of time.
• T-helper cells:-
• T-lymphocytes, can help the B-lymphocytes to be activated by the
antigen.
• .٥ Se cretion of lymphokines:
• Interferon: antiviral.
• Colony stimulating factor: stimulate bone marrow cells.
• Macrophage factor: antibacterial.
• ٦ . They act as macrophage attracting cells .
Dr. Amal M. Moustafa, , Department of Histology & Cytology